Device for the manufacture of metal cylinders

ABSTRACT

A device for manufacturing metal cylinders and in particular for closing one end of a tubular metallic piece, which comprises a chuck for holding the other end of the piece and a forming head with at least two idle rolls having a concave profile. In a first embodiment the axis of each roll lies in a plane passing through the axis of the piece to be worked. In a second embodiment the axis of each roll passes outside of the plane passing through the axis of the piece and through the median point of the arc of contact between roll and piece and preferably forms an angle comprised between 0* and 30* with the plane passing through the axis of the piece to be worked.

United States Patent [191 Groppini DEVICE FOR THE MANUFACTURE OF METAL CYLINDERS [76] Inventor: Diego Groppini, Via Stelvio,

Dalmine, Italy [22] Filed: July 3, 1972 21 Appl. No.: 268,738

[30] Foreign Application Priority Data July 9, 1971 Italy 26804/71 [52] US. Cl 72/84, 72/126, 228/60 [51] Int. Cl B2ld 41/04 [58] Field of Search 228/60; 72/80, 84, 86, 110, 72/111,112,125,126

[5 6] References Cited UNITED STATES PATENTS 1,436,489 11/1922 Ferrier 72/126 2,325,522 7/1943 Lauer at al.

2,408,596 10/1946 Bednar et a1. 2,443,416 6/1948 DeWilde et al.... 2,568,991 9/1951 Dewey 228/60 [451 Feb. 26, 1974 FOREIGN PATENTS OR APPLICATIONS 577,311 9/1924 France 72/86 Primary ExaminerLowell A. Larson Attorney, Agent, or Firm-Kenyon & Kenyon Reilly Carr & Chapin 5 7 ABSTRACT A device for manufacturing metal cylinders and in particular for closing one end of a tubular metallic piece, which comprises a chuck for holding the other end of the piece and a forming head with at least two idle rolls having a concave profile. In a first embodiment the axis of each roll lies in a plane passing through the axis of the piece to be worked. In a second embodiment the axis of each roll passes outside of I the plane passing through the axis of the piece and through the median point of the arc of contact between roll and piece and preferably forms an angle comprised between 0 and 30 with the plane passing through the axis of the piece to be worked.

7 Claims, 5 Drawing Figures PATENTEI] FEB 2 6 I974 sum 1 OF 5 PATENTEDFEBZSIW 3,793,863

SHEET 2 [1F 5 Fig. 2

PATENTED FEB26 I974 SHEET 3 [IF PATEN-TEUFEBZESIQM 793,863-

SHEET 5 0F 5 DEVICE FOR THE MANUFACTURE OF METAL CYLINDERS BACKGROUND OF THE INVENTION The present invention concerns a device for the manufacture of metal cylinders starting from a tubular piece, and in particular a device for closing one end of said tubular piece in order to form the bottom of the cylinder.

It is known that metal cylinders, such as gas cylinders are formed essentially of a hollow cylindrical body having a bottom that can be shaped in various ways, and a neck suitable for the incorporation of the closing valve. The formation and closing of the bottom of the cylinder is one of the most delicate operations in the manufacturing cycle.

In the conventional technique for such operations various methods are used. One of the devices known in the art, currently called nose-former, comprises essentially a rotating head, arranged to receive the end of the original tube placed horizontally, and a forming arm placed at the opposite end of the tube. Such a forming arm, which supports at one end an idle roll with flat or convex profile, is mounted on a plate which is able to move in an are around a vertical axis, while the plate performs only horizontal movements parallel to the axis of the worked piece. That known device is used by initially bringing the idle roll into contact with the edge of the tube, previously heated and kept rotating, and then imparting to the roll itself a back-and-forth movement along ever-increasing arcs of a circumference. At the completion of every passage of the roll, the armcarrying plate moves toward the piece exerting a pressure upon it. When the amplitude of the arc along which the roll is made to work reaches 90, the complete closing of the bottom of the cylinder is achieved. Continuing further the advance of the arm-carrying plate, one can obtain an upsetting of the thickness of the bottom to the desired amount.

The heretofore known devices of this type offer the inconvenience of a limited productivity due to the use of one roll only, which furthermore is forced to make long curved paths. That results in lengthy operational cycles which, combined with the necessity of always keeping the piece in process hot, lead to excessive manufacturing costs. In the case of such devices, moreover, frequent interruptions for maintenance are required to maintain the efficiency of the mechanism which con trols the curved movements of the roll and on which depends the precision of the forming.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a device which is essentially exempt from the above-cited inconvenineces of the conventional devices. Such object is achieved by providing a device in which the mechanism for closing the bottom of the tube comprises at least two rolls which carry out their function without having to make the well-known curved trips back and forth. The forming rolls of the device according to the present invention in fact carry out their action over a definite area of the bottom being formed and for this reason their movement occurs solely parallel to the axis of the tube under process.

The device according to the present invention comprises a chuck for holding the end of the tubular piece made to turn on its own axis, a forming head movable along the axis of the piece and at least two forming idle rolls having a concave profile, which are part of said forming head. The concave profile of each roll corresponds perfectly to a different partial section of the external convex profile of the bottom to be formed, so that each forming roll works a distinct circular area of the bottom while it is being formed. The different distinct circular areas slightly overlap, so that together they cover the entire external surface of the bottom of the cylinder to be formed. The axis of each forming roll has appropriately a fixed spatial inclination.

BRIEF DESCRIPTION OF THE DRAWINGS Further characteristics, objects and advantages of the present invention will be fully understood from the following detailed description of some of its possible embodiments referring to the attached drawings in which:

FIG. 1 is a side elevation view of a device according to the present invention;

FIG. 2 is a top plan view of the same device as shown in FIG. 1;

FIG. 3 is a more detailed, partly sectional view of the same device as shown in FIG. 1;

FIG. 4 is a detailed, partly sectional view of a different embodiment of the device according to the present invention; and

FIG. 5 is a schematic view of a further embodiment of the device of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS. 1 and 2, the device according to the present invention comprises a chuck 1 which is provided with jaws 2 for holding the end of the tubular piece 3 to be closed which in the figures is indicated with dotted lines in an imaginary position. The chuck l is driven by a motor which, for the sake of simplicity, is not shown in the drawings. In front of the chuck l is located a forming head 4 which can slide on table 5 parallel to the axis of the piece 3. On the forming head 4, which is activated by a hydraulic cylinder 6, there are located the individual brackets 7, 8 and 9 positioned at various angles and on which the idle rolls 10, 11 and 12 are mounted. In the embodiment shown in these figures, the forming rolls are three, but there could also be two or more than three. As shown, each roll has an axis disposed at an angle to the axis of the tubular piece 3 which is different from the angle of the other of the roll axes to the axis of the piece 3. Also, each roll 10, l 1, 12 has a different concave profile from the other of the rolls 10, ll, 12.

The operation of forming the bottom of the cylinder is performed by placing the tubular piece 3, previously heated at one end, with the cold end inserted into the chuck 1. Then the chuck 1 is caused to rotate and subsequently the forming head 4 is caused to advance progressively along the table 5 toward the heated end of the tubular piece 3. In this manner the idle rolls 10, 11 and 12 of head 4 are brought into contact with the hot edge of tubular piece 3 and produce the gradual shaping in accordance with their respective profiles. Continuing the advance of head 4 the piece 3 becomes completely closed and with the formation of a convex bottom 13. If the head 4 is caused to advance further after the closing of bottom 13, a perfect closing of the latter with a certain amount of upsetting is obtained.

The forming operation is shown in greater detail in FIG. 3 in which, for the purpose of illustration, two work rolls only 10 and 11 are shown, carried by supports 7 and 8 mounted on head 4 which slides on table 5. The cross-section of the bottom 13 of tubular piece 3 is shown during the work stage, for which reason there is a remaining hole 14 which will subsequently be completely closed through further advancing of the head 4 on the table in the direction of the arrow 15. Arrow 16 indicates the direction of rotation of piece 3, while arrows 17 and 18 indicate the direction of rotation of forming rolls and 11.

The axis of each roll can lie in a plane passing through the axis of piece 3 and be respectively parallel to the tangent line led in such a plane through the median point of the arc of contact between roll and piece. In FIG. 3 the axes A-B of roll 10 and CD of roll 11 are respectively parallel to the tangent lines E-F and GH at the arcs P-Q and R-S of contact between the rolls and piece 3 in their respective median points.

Further it was found advantageous, to reduce the extent of the relative slipping and simultaneously improve the forming of the bottom, that the axis of the forming roll, while remaining in the same plane as the axis of the piece, forms with the above-mentioned tangent line an angle comprised between 0 and 20, having the vertex turned toward head 4. In FIG. 4 axis A-B' of roll 10', and the axis C'D of roll 11 form with tangent lines E'-F and GH an angle having the vertex turned toward forming head 4.

In the embodiment so far described, the forming rolls all have their own axis in the same plane with the axis of the piece 3 under process. However, in accordance with a further preferred embodient of the invention, the axis ofeach forming roll is located outside the plane passing through the axis of the work piece 3 and through the median point of contact between roll and piece. The axis of the roll forms with said plane an angle preferably comprised between 0 and and such that the peripheral speed of the roll at said median point has a component along the axis of piece 3 which is directed toward the chuck 1. Such embodiment is shown in FIG. 5 in which the forming rolls l0 and 11" have their axes not in the same plane with that of the work piece 3.

It is obvious that the embodiments above-described and shown in the attached drawings have been given only by way of on-limiting examples of the present invention. A possible modification for example would be an embodiment in which the chuck head 1 is fixed while the forming head is caused to rotate around the axis of piece 3.

What I claim is:

l. A device for closing one end of tubular metal pieces in the manufacture of cylinders, comprising a chuck means to hold the piece, and a forming head movable along the axis of the piece, said forming head comprising at least two forming idle rolls having their axes at a fixed angle in space, each said roll axis being disposed at an angle to said axis of said piece different from the angle of the other of said roll axes to said axis of said piece and each roll having a different concave profile from the other of said rolls.

2. A device in accordance with claim 1, wherein the axis of each forming roll lies in a plane passing through the axis of the piece to be worked.

3. A device in accordance with claim 2, wherein the axis of each forming roll is parallel to the tangent line through the median point of the arc of contact between roll and piece, led in said plane passing through the axis of the piece.

4. A device in accordance with claim 2, wherein the axis of each forming roll forms an angle of O-20 with the tangent line through the median point of the arc of contact between roll and piece, led in said plane passing through the axis of the piece.

5. A device in accordance with claim 1, wherein the axis of each forming roll is placed outside of the plane passing through the axis of the piece and through the median point of the arc of contact between roll and piece.

6. A device in accordance with claim 5, wherein the axis of each forming roll is inclined of an angle of from 0 to 30 with the plane passing through the axis of the piece and through the median point of the arc of contact between roll and piece.

7. A device in accordance with claim 6, wherein the component of the peripheral speed of the roll at said median point along the axis of the same piece, is directed toward said chuck means.

=l l= l =l 

1. A device for closing one end of tubular metal pieces in the manufacture of cylinders, comprising a chuck means to hold the piece, and a forming head movable along the axis of the piece, said forming head comprising at least two forming idle rolls having their axes at a fixed angle in space, each said roll axis being disposed at an angle to said axis of said piece different from the angle of the other of said roll axes to said axis of said piece and each roll having a different concave profile from the other of said rolls.
 2. A device in accordance with claim 1, wherein the axis of each forming roll lies in a plane passing through the axis of the piece to be worked.
 3. A device in accordance with claim 2, wherein the axis of each forming roll is parallel to the tangent line through the median point of the arc of contact between roll and piece, led in said plane passing through the axis of the piece.
 4. A device in accordance with claim 2, wherein the axis of each forming roll forms an angle of 0*-20* with the tangent line through the median point of the arc of contact between roll and piece, led in said plane passing through the axis of the piece.
 5. A device in accordance with claim 1, wherein the axis of each forming roll is placed outside of the plane passing through the axis of the piece and Through the median point of the arc of contact between roll and piece.
 6. A device in accordance with claim 5, wherein the axis of each forming roll is inclined of an angle of from 0* to 30* with the plane passing through the axis of the piece and through the median point of the arc of contact between roll and piece.
 7. A device in accordance with claim 6, wherein the component of the peripheral speed of the roll at said median point along the axis of the same piece, is directed toward said chuck means. 